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D&D 5E Perception, Passive Perception, and Investigation

clearstream

Be just and fear not...
Supporter
Personally, I use a couple of houserules to avoid some of these issues.

First, I let Observant give advantage on active Perception and Investigation checks, in addition to passive checks. I do this because I don't want the utility of the feat to depend heavily on whether I call for an active check or use a passive check. (As a general principle, I don't want the outcome of an in-game action to be dependent on the choice between two different resolution methods.)
Isn't the outcome the same, if passive is the floor? It seems like your choice on that is cornering you into modifying the feat.

Second, in addition to deduction, I let Investigation also apply to situations covered by the old Gather Information skill, and I also let it work as a general-purpose Research skill (broader than just finding hidden fragments of knowledge). I find this gives the Investigation skill enough alternative uses that I don't have to go out of my way to design traps and other game elements in a way that makes Investigation useful--instead I can just design traps with the builder's IC goals/resources in mind.
Are you saying here - we don't want some traps that need Investigation, and some that do not? If so, that was the kind of consideration that just lead me to say it is consistently Investigation for artifacts.

A bad way to rule in my view is where Perception lets a character notice say some fine seams in the wall, but they would still need their Investigation to know they signified a secret door and how to open it. Either compounding the difficulty, or halving it, depending on if both must succeed, or success with either does the work. After many sessions I landed on just saying - it's Investigation for an architectural feature like a secret door because even if you did notice the seams, it was still going to use that skill at some point. I suppose one imagines the character noticing there is an inexplicable void between rooms, and putting that together with other suspicious features... or whatever.

My starting point was more as some other posters rule... but it just created inconsistencies for me in play. It's interesting how often I come back to consistency as a measure of a good ruling.
 

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Xetheral

Three-Headed Sirrush
Isn't the outcome the same, if passive is the floor? It seems like your choice on that is cornering you into modifying the feat.
Not quite. Setting the passive (with the +5 from Observant) as a floor for an active check has a very different statistical distribution than simply granting advantage on the active check. If I set the passive as a floor, then players would always prefer active checks to passive, and my goal is to make the choice of active/passive not substantially affect the outcome.

For reference, I always roll versus passives on my end--I never compare a passive score to a fixed DC--so the distributions of (e.g.) a trap rolling against a passive+5 or a player rolling with advantage versus a static DC are kinda/sorta equivalent. (Technically the passive+5 is still advantageous, but for typical combinations of bonus vs DC, the odds are pretty close.) The one place that doesn't work is an active Search action vs the original Dex (Stealth) check, but in that particular case the rules effectively impose the passive as a floor anyway, since the original Dex (Stealth) check to become hidden would have failed if it didn't beat the character's passive.

Are you saying here - we don't want some traps that need Investigation, and some that do not? If so, that was the kind of consideration that just lead me to say it is consistently Investigation for artifacts.
I'm fine with some traps requiring investigation, and others not. I simply don't want to feel like I need to force any of the former into the game just to make Investigation worthwhile. And since Gather Information and Research come up pretty frequently in my games (they're common player-driven methods to get a leg up on the opposition), I needed a proficiency for them anyway, and Investigation is a great thematic fit.

A bad way to rule in my view is where Perception lets a character notice say some fine seams in the wall, but they would still need their Investigation to know they signified a secret door and how to open it. Either compounding the difficulty, or halving it, depending on if both must succeed, or success with either does the work. After many sessions I landed on just saying - it's Investigation for an architectural feature like a secret door because even if you did notice the seams, it was still going to use that skill at some point. I suppose one imagines the character noticing there is an inexplicable void between rooms, and putting that together with other suspicious features... or whatever.
I agree sequential perception and investigation checks are usually a bad idea. The (rare) sorts of traps where investigation would come into play at my table are set-pieces to be interacted with, rather than mere obstacles. (After all, if someone went to the trouble of designing and building a trap with a mechanism complicated enough to be difficult to understand, presumably it does something important.)

My starting point was more as some other posters rule... but it just created inconsistencies for me in play. It's interesting how often I come back to consistency as a measure of a good ruling.
I too am all in favor of consistency, which is why I put so much emphasis trying to make sure that both active and passive checks have similar chances of success. That way I can just pick the resolution method that seems best at the time.
 

clearstream

Be just and fear not...
Supporter
Not quite. Setting the passive (with the +5 from Observant) as a floor for an active check has a very different statistical distribution than simply granting advantage on the active check. If I set the passive as a floor, then players would always prefer active checks to passive, and my goal is to make the choice of active/passive not substantially affect the outcome.
Is it right then that in your campaign there is no cost for using the skill actively? It doesn't take any extra time to do so?
 

Xetheral

Three-Headed Sirrush
Is it right then that in your campaign there is no cost for using the skill actively? It doesn't take any extra time to do so?
Why would the resolution method affect the time a skill takes? With one explicit exception in the rules, discussed below, what the character is doing IC doesn't depend on the OOC resolution method. So, for example, searching 50 meters of hallway for traps takes the same time for the character regardless of whether I call for a single passive check representing the repeated task, or multiple active checks.

The only place that changes is the specific situation where the passive score is being used as the DC for an enemy check (e.g. Dex (Stealth) to hide) which takes no action on the part of the character. Taking the Search Action takes an Action, but gives a second chance (in the form of an active check) to find someone hidden that already beat the character's passive score. So the only place where the action cost is different is where the rules (effectively) build-in the passive-as-a-minimum rule.
 

clearstream

Be just and fear not...
Supporter
Why would the resolution method affect the time a skill takes? With one explicit exception in the rules, discussed below, what the character is doing IC doesn't depend on the OOC resolution method. So, for example, searching 50 meters of hallway for traps takes the same time for the character regardless of whether I call for a single passive check representing the repeated task, or multiple active checks.
I guessed that might be a difference between how we play it. So in my game, the passive value is for the ongoing awareness of a normally cautious party. If they want an active check, they need to put extra effort into it. I still don't quite follow your method. Can you correct or confirm the following please?

Clement - I stop searching for secret doors with the others, and keep a look out for interlopers
Clearstream - roll in the tower and tell me your Wisdom (Perception) modifier

versus

Clement - I stop searching for secret doors with the others, and keep a look out for other interlopers
Xetheral - okay, I will note your passive Wisdom (Perception), you'll spot any whose Stealth that number beats
 

Xetheral

Three-Headed Sirrush
I guessed that might be a difference between how we play it. So in my game, the passive value is for the ongoing awareness of a normally cautious party. If they want an active check, they need to put extra effort into it. I still don't quite follow your method. Can you correct or confirm the following please?

Clement - I stop searching for secret doors with the others, and keep a look out for interlopers
Clearstream - roll in the tower and tell me your Wisdom (Perception) modifier

versus

Clement - I stop searching for secret doors with the others, and keep a look out for other interlopers
Xetheral - okay, I will note your passive Wisdom (Perception), you'll spot any whose Stealth that number beats
My verbal response to Clement would probably be "Sounds good!", but you've got the mechanics right. Note that Clement would still get his passive perception to notice threats even if he just said "I stop searching for secret doors" so long as he didn't declare anything else that would be distracting--I treat "watching for interlopers" as the default action declaration. Also note that, while searching for traps, a character does not get their passive perception at all at my table--out-of-combat, enemy stealth checks automatically succeed against a distracted character.
 

clearstream

Be just and fear not...
Supporter
My verbal response to Clement would probably be "Sounds good!", but you've got the mechanics right. Note that Clement would still get his passive perception to notice threats even if he just said "I stop searching for secret doors" so long as he didn't declare anything else that would be distracting--I treat "watching for interlopers" as the default action declaration. Also note that, while searching for traps, a character does not get their passive perception at all at my table--out-of-combat, enemy stealth checks automatically succeed against a distracted character.
So is it right that characters never get active perception against creatures? Only against things like traps?
 

Pauln6

Explorer
The way I have always done it is to apply a higher DC to perception checks that would be easier to find with investigation. So sure, you might notice that a section of wall is a slightly different colour or there is a barely noticeable line where the door is but you would have a much higher chance of making deductions from closer investigation, running your fingers over the wall etc.

+5 is a good baseline but it can vary.
 

Xetheral

Three-Headed Sirrush
So is it right that characters never get active perception against creatures? Only against things like traps?
They'd get an active Wis (Perception) check if they declare an action that wasn't ongoing (since ongoing tasks are what passive checks are for) and the normal prerequisites for making a check are met.

So if the PC declares that they are doing a walkthrough and visual inspection of a grove to find out what is there, and I as a DM know that there is a hidden creature there, I would have to decide whether I think it's impossible/possible/certain for the character to find the creature, and if it's possible I'd call for a WIS (Perception) check. (In this example I think the consequence for failure is a given.) As the character would have already noticed the creature had the creature's hide check failed (assuming the grove is small/quiet enough that everything is in hearing range), this active check effectively has a minimum floor of the character's passive perception. The in-combat analogue would be taking the Search action.

Other situations where an active WIS (Perception) check to notice creatures might apply include: going up to the top of a tower to scan the horizon for movement (as opposed to standing watch, which would be passive), or looking for someone specific, such as spotting a friend in a heavy crowd (as opposed to watching the crowd until the friend is seen, which would be passive).
 

clearstream

Be just and fear not...
Supporter
They'd get an active Wis (Perception) check if they declare an action that wasn't ongoing (since ongoing tasks are what passive checks are for) and the normal prerequisites for making a check are met.
So if I search repeatedly, I can't do better than my passive. But if I search once, I might beat it?
 


I mean, Wisdom is functionally the perception attribute in 5e. It encompasses interpersonal awareness as well as sensory awareness, but that’s what its uses cover.
It isn't really, though. If it were, Wisdom would be a core attribute for Rogues, not Clerics. Elves would get bonuses to Wisdom. The current incoherent system means Clerics make the best scouts and guards. It doesn't make any sense.
 

6ENow!

The Game Is Over
Passive it to "notice something that gets your attention". Active when you try and discern what it was that grabbed your attention. Investigation is when you find out exactly what grabbed your attention and now you want to do something about it.
Nothing wrong with doing it this way, certainly.

My issue with resolving things thusly is that you require three checks (possibly) and failing anywhere along the way denies the PC progress. Now, how do you handle the concept of "lack of progress instead of failure"? Can a PC "keep looking" and eventually find it? Do they have to fail by 5 to deny them any hope of success?

Another issue is skill clumping (or the lack thereof). Athletics, for example, involves three very different skills: climbing, jumping, swimming for movement, as well as lifting and throwing possibly depending on your view. But, we have perception and investigation (and passives for both) instead of one "Notice" or something skill. We also have Deception, Intimidation, and Persuasion; all of which could be clumped into "Influence" just as several skills are clumped into Athletics. After all, you influence others either by deceiving, intimidating, or persuading them-- the result is the same, just the avenue differs.

So, here's the point I was trying to make: The litmus test, at least in this game, is not "does the GM know there is a clue", but instead, "does the GM expect there might be a clue, whether the GM specifically placed it or not".
So, to be clear, you are more thinking along the lines of this:

As DM, I know a man heard the PCs coming and just quickly hid behind the tapestry There will be signs of his movements and it is not important what they are. When the PCs enter, if any have a high enough passive Investigation (?) I will inform the player their PC finds clues of a person recently being there (whatever those clues are) and if the passive Investigation is not high enough, I'll ask for a roll only if the players say they are looking the room over, etc.

Because the GM should know, IMO, whether there might be something there or not--there shouldn't be an "expect"(ation) on the DMs part as I see it--or I am still not getting your point clearly enough.

We are talking about an excessive case to make the point that the idea that only that which the GM describes is relevant is kind of bogus. Because the GM gives, at best, a sketch of the room, with minimal details. But the PCs should see it in 4k HD, right?
(Emphasis mine)

Yes, I completely agree with this, which is why passive scores should be used IMO. Other things could be relevant, but even if a PC rolls well enough or has a high enough passive score to find something, it is still up to the DM what those things are (i.e. what is relevant). Or, the DM can gloss over the details and just confirm the final result.

Anyway, this is why I use passive scores as I do. The PCs might notice something the player doesn't think to ask for even after given my description. If the passive score indicates the PC might notice whatever it is, I'll ask the player to make a check. If the roll fails, so be it. If if succeeds, then I'll reveal whatever it is the PC found the player never thought to look for.

Again, my preference is for passive scores to not be automatic. It removes some agency for the player to participate more when they can rely on the PC's passive scores.
 

robus

Lowcountry Low Roller
Supporter
Player: "Ha! Ok, I'm going to start looking for bricks or rocks in the wall that are different colours, or smoother, or something. I'm looking to see if it can open from this side"
DM: "You press various rocks that catch your attention...what's your Investigation? Make a check for me..."
Player: "Ok...I got a total of... 15"
The interesting part you’ve not addressed is, what was the possible consequence of failure in the investigation?
 

Charlaquin

Goblin Queen
It isn't really, though.
It literally is. It says “Wisdom measure(s) perception and insight,” “Wisdom reflects how attuned you are to the world around you and represents perceptiveness and intuition,” and “A Wisdom check might reflect an effort to read body language, understand someone’s feelings, notice things about the environment, or care for an injured person.”
If it were, Wisdom would be a core attribute for Rogues, not Clerics.
Traditionalism is a hell of a drug.
Elves would get bonuses to Wisdom.
Wood elves do, and other elves get proficiency in perception (a specific use of Wisdom).
The current incoherent system means Clerics make the best scouts and guards. It doesn't make any sense.
Nobody ever said D&D made sense.
 

robus

Lowcountry Low Roller
Supporter
First point I’d like to make is if the dice are giving you nonsensical answers then you’re asking them to answer nonsensical questions. They are a random number generator not a fortune telling device. Only have the players roll when there is good reason for the outcome of their declared action to be uncertain and there is a cost of them failing. This is why we’re always rolling in combat because everything is pretty chaotic and uncertain (and the cost of failure is the opponents have more chances to hit back!)

So is it right that characters never get active perception against creatures? Only against things like traps?
So with my preamble in mind, what does this mean? Players roll perception against any action that requires using their senses to protect themselves from possible harm or setback, animal, vegetable or mineral.
So if I search repeatedly, I can't do better than my passive. But if I search once, I might beat it?
Again, getting nonsensical results is a sign that your chosen resolution mechanic has gone off the rails. :)

Searching repeatedly in the same location (with only the cost of time) will locate the item (assuming the DM is not playing games with the players and them waste game time on pointless exercises).

Passive perception (or investigation) is a tool for modeling constant perception in a risky situation that is changing over time (and your PC wants to remain vigilant during that period). For example, traveling, exploring, keeping watch (and yes keeping watch is a situation that changes over time because while the PC is pretty stationary various other creatures are coming and going and making noise and the PC is having to constantly make judgement calls as to whether it is a legitimate threat).

A single check is applied when there is meaningful consequence for failure in that moment. For a search it might be that the PCs have just made it into a study and they need to find an item before the guard returns and notices the light under the door (or whatever). If the check succeeds they find the item and get out before the guard returns. If they fail they need to make a choice of leaving without the item (and eluding the guard) or stay and finish the search (which will now succeed) but with the consequence that the guard is now at the door and rattling the handle (and probably raising the alarm).
 

Hriston

Dungeon Master of Middle-earth
Somewhat seconding @Charlaquin here:

It isn't really, though. If it were, Wisdom would be a core attribute for Rogues, not Clerics.
The rogue's shtick is avoiding notice, not being good at noticing others.

Elves would get bonuses to Wisdom.
Wood elves do, and all elves are proficient in Perception which is the aspect of Wisdom that's specifically about noticing things.

The current incoherent system means Clerics make the best scouts and guards. It doesn't make any sense.
You'd have to unpack what you think doesn't make sense. Shouldn't clerics be good at looking out for their flock?
 

The interesting part you’ve not addressed is, what was the possible consequence of failure in the investigation?
Not the original commenter, but IMO the interesting consequence is being unable to open the door. Most people hate that, but there are some puzzle you just can't solve.
 

robus

Lowcountry Low Roller
Supporter
Not the original commenter, but IMO the interesting consequence is being unable to open the door. Most people hate that, but there are some puzzle you just can't solve.
Sure if there is some special key or pattern sequence that searching the rest of the dungeon would reveal and cause an “aha” moment, exploration-oriented players love that. But unable to open it based on a failed skill check when they have plenty of time...?
 

6ENow!

The Game Is Over
Sure if there is some special key or pattern sequence that searching the rest of the dungeon would reveal and cause an “aha” moment, exploration-oriented players love that. But unable to open it based on a failed skill check when they have plenty of time...?
Why not? Haven't you ever lost your car keys or something else, damned no matter how long you look?
 

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